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Electric field please help

  • Thread starter BuBbLeS01
  • Start date
  • #1
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Electric field....please help!!!!

Homework Statement


A 0.75 g plastic bead is charged by the addition of 8.28×10^10 excess electrons. What electric field (strength) will cause the bead to hang suspended in the air?


Homework Equations





The Attempt at a Solution


Doesn't E have to equal the weight? So would I just calculate the weight of the bead? That seems to easy though...
 

Answers and Replies

  • #2
Shooting Star
Homework Helper
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The weight and the charge. Also, remember Force = E*q.
 
  • #3
602
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So...
(K*Q1*Q2) / R^2 = (KQ1) / R^2 * Q
And then I solve for Q?
But then I get Q2 = Q?? I am confused...
 
  • #4
Shooting Star
Homework Helper
1,977
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Let E be the unknown electric field. Then what is the force it exerts on a charge q? I've already told you...
 
  • #5
602
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E = Force / Q
Force = K*Q1*Q2 / r^2
 

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